The travelers of the stars (also known as builders) are an advance future human species appearing in the book Man After Man, being the distant descendants of the human beings who left the earth.
In the book it is specified that these beings are descendants of the humans that participated in the project of colonization of the stars, one of the 37 ships that settled in a habitable planet some centuries after they have been thrown. Due to the conditions of its planet such as atmosphere, gravity and resources, they underwent biological changes through genetic engineering to adapt to such conditions, but is unknown, however, what would have been its world of origin and its evolutionary history.T hese beings at some point in the last millions of years had begun to explore other star systems in search of new habitable planets, which colonized and used their resources for their own subsistence .One could speculate on the reasons that led them to do that is because they probably sold out the resources of their own home planet, leaving it uninhabitable eventually.
After 5 million years, the travelers of the stars find the planet earth, yet they are unable to recognize that this is the planet of their ancestors. In a few hundred years they radically transform the Earth's surface, building huge cities on land and oceans, transforming fauna into work and food tools, collecting all available resources, and gradually changing the atmospheric conposition. At the end, in other hundred years, eventually they leave the Earth, probably in search of another planet to use, leaving the world in ruins and with only a handful of survivors in the deep ocean.